If possible, separate the goats & sheep. Goats need more copper than sheep. A loose mineral is better for goats. It is hard for them to get what they need form a block. If you continue giving the sheep mineral, you are going to have to give the goats copper in another form such as boluses. The best would be to get them in a pen by themselves & give each animal the minerals they need. I know that is sometiems hard. If you give the sheep a goat mineral you will kill them because it has too much copper. And giving a goat a sheep mineral can eventually kill htem because they will not be getting enough copper. Also, it is not necessary to give salt plus minerals. The minerals will have the salt they need. Otherwise they will tend to eat the salt & then skip the minerals.

I give my goats a pressed mineral block that contains (among other things) salt, copper, and selenium. It works better for my small herd than loose minerals. I used to provide a regular old hard mineral block but the mineral issues kept popping up. I had one doe with "racoon eyes" aka bald around the eyes. I switched from the hard mineral lick to loose minerals which nobody except my little Nigerians would touch. Then I switched from loose to my current pressed block and everyone loves it. No more racoon eyes, bald tails, or rotten coats. I'm glad I switched in time to avoid death and selenium deficiency problems like White Muscule Disease. I knew people who had a kid born with WMD (white muscule disease, not armed and dangerous).
Sheep minerals shouldn't contain copper, but goats need copper. Some areas have soil that is rich in selenium, so that might not be a problem for you, but I'm not sure about copper. Some people sprinkle minerals on their goats grain, but be sure to read the label an figure out how much to give, excess minerals can be as deadly as no minerals, and quicker to kill, too.
I know that there are mineral injections, like multi-min, you can give goats. You might try that.
Best wishes!
~Carrie C.

You might want to try a beef mineral (usually has enough copper for goats) and set it on a shelf with a rail under it so the goats would have to stand on their hind feet with front feet on the rail to get at the mineral. It's my (limited) sheep experience that sheep will not stand on their hind legs to eat or investigate something, but goats always will.